Particle grading effect on properties of reactive MgO‐bonded castables

Abstract

AbstractRefractory matrix is a key factor in determining the properties and performance and thus the lifetime of refractory materials. The particle gradation affected both the matrix composition and microstructure. In this study, six particle gradations of high‐alumina castables were prepared based on Andreasen's model (q = 0.22, 0.24, 0.26, 0.28, 0.30, and 0.32). The influence of particle gradation on properties of high‐alumina castables bonded with 4.0 wt% reactive MgO (RM) was investigated with respect to the difference in matrix composition and microstructure. The results show that castables with q values of 0.24 and 0.26 exhibited better physical and mechanical properties after curing and drying. The castables with a q value of 0.22 showed the best volume stability after firing at 1600°C, whereas, castables with a q value of 0.24 exhibited the highest mechanical strength, and residual CMOR ratio after thermal shock testing. Based on the property analyses of castables, the optimal q value of RM‐bonded castables would be around 0.24.